Gas turbine engines generally include a compressor, such as an axial compressor, to pressurize inflowing air. Axial compressors may include number of rotor segments adjacent and coupled to each other in the axial direction. The outer rim of the rotor segments may utilize expansion slots to help reduce hoop stresses on the outer rim. As the compressor operates, air enters the expansion slots, and may mix with and increase the temperature of cooling air within the rotor assembly. Cooling of the inner and outer rim may tend to prevent fatigue and potentially extend the life of the material of the rims. Hot air may escape through, for example, the expansion slots, and thereby reducing the cooling effect of the cooling air and/or interrupting the aerodynamic flow of air through the compressor.